Most devices for the rapid vaporization of a liquid use one or more electric heaters plunged in a relatively large volume of water and therefore have a relatively long vaporizing phase and are relatively cumbersome. They use safety systems for the absence of liquid, they must necessarily be used in the horizontal position, they are relatively expensive not only in so far as their design is concerned but also their maintenance and they have mediocre efficiency, particularly when they are used at a low rate of activity and because of the heat losses due to the relatively large surfaces of the vapor generators.
Other types of device are further known for the rapid vaporization of a liquid including a porous body impregnated with liquid to be vaporized and electric heating means for heating the porous body and causing therein rapid vaporization of the liquid which migrates continually through the porous body under the effect of its pumping and suction capabilities, by capillarity, from a liquid layer situated at a lower level than that of the porous body and in which the porous body is partially plunged. Such devices are described for example in Patent Nos. FR-A-2 341 340 and FR-A-2 420 731.
These devices however, have the drawback of only being able to function in a horizontal position, because of the permanent presence of the liquid layer and of not allowing a desired variation profile in time to be obtained of the flow of vapor produced.